Behavior of students in schools seems to have changed due to a breakdown of family life, and also addiction to drugs, TV, computer games.
Though the basic premise of schools hasn't changed, they now go above and beyond the three 'R's' that they used to teach, and schools have now become an extention of a child's family.
Many would say that schools were designed to keep young people from learning how to think critically, and I would agree with this. Combine this with all of the propoganda from the media outside of school, and it's a recipe for causing much confusion in young people.

John Taylor Gatto, a former New York city schoolteacher, writes on this subject in his book, 'Dumbing Us Down: The Invisible Curriculum of Compulsory Schooling.' Here are a few exerpts from chapter one:

"After an adult lifetime spent teaching school, I believe the 'method' of mass schooling is its only real content. Don't be fooled into thinking that good curriculum or good equipment or good teachers are the critical determinants of your son's or daughter's education. All the pathologies we've considered come about in large measure because the lessons of school prevent children keeping important appointments with themselves and with their families to learn lessons in self-motivation, perseverance, self-reliance, courage, dignity, love--and lessons in service to others, too, which are among the key lessons of home and community life.
Thirty years ago, these lessons could still be learned in the time left after school. But television and the stresses peculiar to two-income or single-parent families has swallowed up most of what used to be family time as well. Our kids have no time left to grow up fully human and only thin-soil wastelands to do it in.
A future is rushing down on upon our culture that will insist all of us learn the wisdom of nonmaterial experience; a future that will demand as the price of survival that we follow a path of natural life economical in material cost."

Gatto also puts this issue in a larger historical perspective:

"Only a few lifetimes ago things were very different in the United States. Originality and variety were common currency; our freedom from regimentation made us the miracle of the world; social-class boundaries were relatively easy to cross; our citizenry were marvelously confident, inventive, and able to do much for themselves independently. We were something special, we Americans, all by ourselves, without government sticking its nose into and measuring every aspect of our lives, without institutions and social agencies telling us how to think and feel. We were something special, as individuals, as Americans.
But we've had a society essentially under central control in the United States since just before the Civil War, and such a society requires compulsory schooling, government monopoly schooling, to maintain itself. Before this development schooling wasn't very important anywhere. We had it, but not too much of it, and only as much as an individual wanted. People learned to read, write, and do arithmetic just fine anyway; there are some studies that suggest that literacy at the time of the American Revolution, at least for non-slaves on the Eastern seaboard, was close to total. Thomas Paines 'Common Sense' sold 600,000 copies to a population of 3,000,000, twenty percent of whom were slaves, and fifty percent indentured servants.
Were the colonists geniuses? No, the truth is that reading, writing, and arithmetic only take about 100 hours to transmit as long as the audience is eager and willing to learn"